Get SBFunction from SBSymbol

I use the get function(s) api to look for sel_registerName, which gives me an SBSymbolContext, but for some reason (probably missing debug info) I don't get a Function, only a Symbol, how do I get an SBFunction from an SBSymbol?

function = symbol.GetStartAddress().GetFunction()

You won't always have a function. You will only have a function if you have debug info. Without debug info you will not get a compile unit, function, block, or line entry.